This invention relates generally to medical gas conditioning systems and, more specifically, to a system for supplying hydration fluid to a hydrator in a medical gas conditioning device.
Inflating a patient's body cavity with a medical insufflation gas distends, or inflates, the body cavity producing an operating region within the body cavity, which enables performance of a minimally invasive surgical procedure on the patient. Douglas Ott et al. U.S. Pat. Nos. 5,411,474; 6,068,609 and 7,066,902 show and describe a medical apparatus that humidifies or otherwise conditions an insufflation gas during such a surgical procedure. Briefly, the patents describe the heating and hydrating of the insufflation gas, i.e. the conditioning of the insufflation gas, before injecting the insufflation gas into a body cavity through an inflation device such as a trocar. In order to hydrate the insufflation gas one injects a charge of hydration fluid into a hydrator where the hydration fluid contacts the insufflation gas and humidifies the insufflation gas before injecting the insufflation gas into the patient's body cavity. In addition, one may heat the insufflation gas thereby bringing the insufflation gas to the proper temperature for insertion into the body cavity. During the medical procedure one periodically injects the conditioned insufflation gas into the patient's body cavity through an inflation device such as trocar in order to maintain the body cavity in an inflated condition since some of the insufflation gases escape from the body cavity during the performance of the surgical procedure.
Laparoscopy is an example of one type of a minimal invasive surgery where one inflates a body cavity with a medical insufflation gas. In a laparoscopic surgical procedure, a surgeon manipulates instruments inside a patient's inflated body cavity through a trocar. The most prevalent medical insufflation gas used in the laparoscopic surgical procedures is carbon dioxide, which is directed into a peritoneal cavity through a trocar. A device called an insufflator regulates the delivery of the carbon dioxide gas to the body cavity. Typically, the insufflator receives an unconditioned medical gas from a gas canister containing a medical grade insufflation gas with the gas typically having water vapor concentrations on the order of 200 parts per million, which is extremely dry. In addition to the insufflation gas being dry, the unconditioned insufflation gas delivered from the gas canister is generally at a temperature less than the ambient temperature. In a typical surgical setting the ambient temperature level of the surgical setting may be about 20° C. and the patient's normal body temperature of 37° C., which results in a large temperature difference between the temperature of the unconditioned insufflation gas and the body temperature of the patient. Studies performed over several decades have produced a large body of evidence that shows that the use of unconditioned insufflation gas, such as carbon dioxide, in laparoscopic surgical procedure results in adverse effects for the patient. However, by conditioning the insufflation gas, with respect to both its temperature and relative humidity, reveals that one can avoid the adverse effects that occur with unconditioned insufflation gas.
As it was assumed that conditioning of the insufflation gas did not provide a physiological benefit to the patient the early medical devices transporting the insufflation gas from the insufflator to the patient consisted of a length of plastic tubing with an inline filter attached to the tubing to block unwanted contaminates from the source of the insufflation gas. Since no conditioning was performed to the insufflation gas the body cavity of the patients was inflated with a cold dry gas. The insufflation systems have evolved to the current state where an insufflation devices can both warm and humidify an insufflation gas such as carbon dioxide gas although other insufflation gases may also be warmed and humidified. Such insufflation systems may increase the moisture content of the gas to near 100% relative humidity. Such gas conditioning systems, which are shown in U.S. Pat. Nos. 5,411,474 and 6,068,609, have resulted in physiological benefits to the patient.
The benefits of insufflation systems, which conditions the insufflation gas, reveal that certain operational requirements of the insufflation system may require disruptions of the medical procedure or at least cause inconveniences. For example, the medical personal may need to separately introduce the hydration fluid into a hydrator in order to hydrate the insufflation gas before the surgical inflation gas flows into the patient's body cavity. Typically, the hydration fluid needs to be introduced into the hydrator before the surgical procedure begins and periodically during the surgical procedure. For example, after an initial hydration of the hydrator, one may add hydration fluid to the hydrator after a threshold condition such as 150 liters of insufflation gas have passed through the hydrator with the threshold condition based on a determination that shows the hydrator can hold sufficient hydration fluid to hydrate at least 150 liters. While the task of periodically supplying hydration fluid to the hydrator does not present an onerous task for medical personnel it has the potential to be accidentally overlooked during the surgical procedure resulting in unhydrated insufflation gas being supplied to the patient. Therefore an apparatus and method that can automatically supply a hydration fluid into the existing hydrators, which may be done on-the-go, would provide a benefit to the medical staff and the patient. Another inconvenience with the existing hydration systems is that, the supply of medical gas to the hydrator needs to be suspended or shut off when supplying the hydration fluid to the hydrator in order to prevent the hydration fluid from being forced through the hydrator and into the patient's body cavity without having an opportunity to being absorbed by the hydration member in the hydrator. The failure of the hydrator to absorb the hydration fluid may have adverse effects including accumulation of fluid on the lens of a visualization device, which is used to during the medical procedure, thereby obstructing the surgeons view of the surgical site.